Package assembly and method of packaging ammonium nitrate



1951 G. P. JACOBSON ETAL PACKAGE ASSEMBLY AND METIIOD OF PACKAGING AMMONIUM NITRATE 2 Sheets-Sheet 1 Filed May 12. 1959 N HMMLWWFIMI mhl 4 m M Q m OE v m lllll INVENTORS GEORGE P. JACOBSON JOSEPH A. SMITH BY QM ATTORNEY 1951 G. P. JACOBSON ET AL 3,010,574

PACKAGE ASSEMBLY AND METHOD OF PACKAGING AMMONIUM NITRATE 2 Sheets-Sheet 2 Filed May 12, 1959 FIG] %N 00 S B E O V C A W J P E G R o E G JOSEPH A. SMITH ATTORNEY United States Patent York Filed May 12, 1959, Ser. No. 812,739 2 Claims. (Cl. 206-65) This invention relates to a method of packaging ammonium nitrate products in which the dangers of fire and explosion during transportation or storage are minimized, and to the resulting package.

Shipping and storage of ammonium nitrate, have been found to present serious hazards and, in spite of care to avoid the occurrence of sparks, fire, or undue restriction of products of combustion, serious accidents have occurred in the past in the course of handling this material. In the Wake of such accidents a number of justifiable but burdensome and expensive restrictions have been imposed on its storage and shipment. For example, ammonium nitrate, classified by the US. Coast Guard as an oxidizing material, and not ordinarily considered explosive or dangerous to handle, has been known to explode if it is caused to burn under conditions permitting excessively high temperatures to occur and preventing free escape of products of combustion. Such conditions tend to occur primarily in the holds of barges or ships, so that in marine transportation, this material, particularly when packaged in combustible containers such as paper bags, must be stored according to strict regulations imposed by Federal authorities, including the use of sweatboard separators, trenching to provide venting flues for products of combustion in case of fire, bracing, chocking, etc., all of which require excessive storage space and contribute to the expense of handling and shipping the material.

A primary object of the present invention is to provide a package assembly and method of packaging ammonium nitrate in which the dangers of fire and explosion are greatly reduced or eliminated.

A further object of the invention is to provide a package assembly and method of packaging ammonium nitrate in which, if fire or explosion should be initiated, it is automatically terminated before serious propagation occurs.

A still further object of the invention is to provide a method for protecting ammonium nitrate from the hazards of fire during transportation and storage, in a simple, relatively inexpensive manner.

A still further object is to provide a safe package assembly and method of packaging ammonium nitrate, in which trenching, venting and the like can be dispensed with.

These and other objects are accomplished according to our invention wherein the ammonium nitrate is first placed into a plurality of essentially cylindrical, water-impermeable flexible-Walled containers which are then sealed with a water-tight seal, and the resulting packages are submerged in water.

In the drawings, FIGURE 1 illustrates, in longitudinal section, a closed barge stowed with a plurality of ammonium nitrate-containing packages stacked one upon another and submerged in water. FIGURE 2 illustrates a similar barge in which the packages are stowed suspended on cables. FIGURE 3 is a cross section, taken along line 33 of FIGURE 1. FIGURE 4 is a cross section taken along line 4-4 of FIGURE 2. FIGURE 5 is a cross section of an open top barge illustrating a package assembly in which the packages are stowed one upon the other in the barge. FIGURE 6 illustrates a ice plan view of the top of a conventional, flexible-walled package suitable for containing the combustible product. FIGURE 7 is a side elevation of the package. FIGURE 8 is a plan view of the bottom of the package.

In the drawings like characters denote like parts throughout. In FIGURES 1-4, numeral 1 illustrates the hull of a conventional barge, having an outer shell 2, inner shell, 3, with vertical supporting members or floors 4, between inner and outer shells. Transverse bulkheads 5 and longitudinal bulkheads 6 separate the barge into reinforced compartments, covered by sliding or otherwise removable hatch covers 7. Bulkheads may be watertight if desired but preferably are swash bulkheads i.e. having holes therein, to permit circulation of water through the entire capacity of the inner shell of the barge. A plurality of flexible containers 8 are closely stacked in the compartments of the inner shell of the barge, one on top of the other as shown in FIGURES 1, 3 and S, and are all completely submerged in water 9. The packages, holding ammonium nitrate products heavier than water, remain submerged by gravity. In FIGURES 2 and 4, flexible packages 8 are shown suspended through lifting eye 10 and supporting hooks (not shown) to cable 12 secured to the inner shell of the barge or to the bulkheads at points 13, and the packages are held sub-merged in Water 9 by the tension of the cables. This arrangement is advantageous for packaged ammonium nitrate products which are lighter than water, the cables serving to hold the packages under water. FIGURE 5 illustrates an open top barge i.e. one with no hatch covers, with Water 9 acting as the only covering for the packages 8 of combustible material within the inner shell 3 of the barge.

In FIGURES 6 to 8, numeral 8 illustrates a conventional flexible package suitable for containing ammonium nitrate products according to our invention. Numeral 14 denotes the flexible side Wall of the essentially cylindrical package, advantageously of natural or synthetic rubber. 15 denotes a lifting eye at the top of the package. Lines 16 represent internal reinforcing cables terminating at anchor eyes 17. Numeral 18 illustrates the threaded cap of a filling connection, 19 represents the cap of an inert gas connection and vent, while numeral 20 illustrates the capped discharge connection of the package.

The packages for the ammonium nitrate product may be of any suitable Water-impermeable and preferably gas-impermeable material, preferably of a flexible, rub ber or, synthetic rubber, composition, which are noncorrosive and preferably shaped essentially in the form of cylindrical drums, which may be rounded at top and bottom as shown, to provide space for water between the containers. If desired, the package may be provided with one or more lifting eyes and may be internally reinforced with flexible cables and the package may be provided with suitable filling. discharging and vent connections. Containers having capacities between about 5 cubic feet and about 300 cubic feet are commercially available. The 70 cubic foot size is especially suitable for marine shipments of ammonium nitrate. The packages, however, may be of any convenient size and are individually filled with predetermined quantities of the ammonium nitrate product by the usual conventional means.

In operation, the flexible drum 8 maybe suspended by its lifting eye, filling connection 18 is opened and ammonium nitrate, usually in solid granular form is charged to the drum through the filling connection in any suitable manner, gas being vented through vent 19.

After the packages are filled with the solid, granular material, the gas vent 19 may be closed, and an inert gas such as carbon dioxide, nitrogen or the like, may be introduced into the interior of the package under moderate pressure, for example, from about'2 ounces sig. to about 3 p.s.i.g., to further reduce fire hazard and to aid in maintaining a more rigid container shape, if desired, but this is not essential.

The filled containers are then sealed as by threaded caps over the vents as shown in the drawings.

The product-containing packages are then loaded into a Water-tight primary container or space, which may be built into the cargo space or hold of a Water-going vessel such as a ship or barge, or may be built into a gondola type railway car or truck trailer if the packages are to be transported, or the water-tight container may be a conventional, stationary storage tank, reservoir or the like.

Either before, after, or during loading of the packages into the water-tight primary container, sufiicient water, either fresh or salt, is introduced into the primary container around the packages to flood the container and cover the packages so that they are completely submerged in the water. If desired, part or all of the water may be introduced into the primary container prior to loading the ammonium nitrate-containing packages, or the packages may be loaded and placed prior to the addition of any water. In many cases, however, it may be desirable to add the Water continuously or intermittently during the loading, for example, to load one layer of packages into a space containing no water, or only part of the final water charge, add water to cover, then add another layer of packages followed'by water addition and so on, to minimize fire or explosion hazard during loading.

The primary container should be water-tight, preferably rigid and preferably closed at the top, although closure is not essential, as in some cases the water may form a suflicient cover for thepackages, as in the case of a barge flooded with Water, for example. The water in the primary container may be circulated, and cooled or heated as desired. Cooling is especially desirable where cargoes are being carried through hot areas such as exist in the vicinity of the tropics.

The packages may be handled for loading by conventional mechanical methods and means such as by cranes and lift trucks, etc. Ordinarily, in loading, suc h packages may be simply stacked one upon the other in the primary container Without separating devices, sweatboards or skids although these may be used if desired. No spacing or trenching for ventilation purposes is necessary. If lifting eyes are present on the packages, it is possible to suspend the packages on cables secured to the walls of the primary'container. The packages may be unloaded by conventional means, as by removing the hatch covers where these are employed, and hooking a crane into the eye of the flexible package or by the use of conventional mechanical tong lifts or the like where the packages are not equipped with lift eyes.

The resulting package assembly of our invention thus is made of a primary, water-tight outer container (e.g. the hold of a barge or ship) having therein, water and a plurality of water-impermeable, flexible, ammonium nitrate containing packages, positioned in said primary container and sub-merged in the water therein.

The package assembly of our invention provides virtually complete protection of the ammonium nitrate, not only from the hazards of fire and ignition, but, by the cushioning effect of the water, greatly reduces or eliminates the efiect of shocks which might tend to detonate the ammonium nitrate.

While the above describes the preferred embodiments of our invention, it Will be understood that departures may be made there-from within the scope of the specification and claims.

We claim:

1. A package assembly for the transportation of ammonium nitrate comprising a primary, water-tight transportable container having positioned therein water and a A plurality of close-packed readily removable water-impermeable inflated flexible-walled packages containing ammonium nitrate, said packages being immersed in said water.

2. A package assembly according to claim 1, wherein said container is a vessel adapted for propulsion on a water surface and said flexible-walled packages are of a composition selected from the group consisting of rubber and synthetic rubbers.

References Cited in the file of this patent 

1. A PACKAGE ASSEMBLY FOR THE TRANSPORTATION OF AMMONIUM NITRATE COMPRISING A PRIMARY, WATER-TIGHT TRANSPORTABLE CONTAINER HAVING POSITIONED THEREIN WATER AND A PLURALITY OF CLOSE-PACKED READILY REMOVABLE WATER-IMPERMEABLE INFLATED FLEXIBLE-WALLED PACKAGES CONTAINING AMMONIUM NITRATE, SAID PACKAGES BEING IMMERSED IN SAID WATER. 